A charging method, a corresponding charging device and various corresponding uninterruptible power systems are provided. The method comprises: controlling a charging circuit to charge a battery string and measuring a voltage of each battery; determining whether a start condition for performing a voltage balancing operation is met based on the voltage values of the batteries, and determining whether the voltage value of any battery is greater than or equal to a first threshold value; whenever the start condition is met, controlling a battery balancing circuit to start performing the voltage balancing operation until the voltage values of the batteries meet an end condition of the voltage balancing operation; and whenever the voltage value of any battery is greater than or equal to the first threshold value, reducing the output energy of the charging circuit until the voltage value of any battery is less than the first threshold value.
Legal claims defining the scope of protection, as filed with the USPTO.
. A charging method, suitable for a battery string consisting of batteries connected in series, comprising the following steps:
. The charging method as claimed in, further comprising the steps of: reducing the output energy of the charging circuit by reducing the output voltage of the charging circuit.
. The charging method as claimed in, further comprising the steps of: when the end condition is met, increasing the output voltage of the charging circuit to a maximum target voltage, and continuing charging the battery string accordingly, wherein the maximum target voltage is greater than an initial target voltage of the charging circuit, the value of the maximum target voltage is a product of the number of the batteries and a maximum chargeable voltage defined by the specification of the batteries, and the value of the initial target voltage is a product of the number of the batteries and a standard charging voltage defined by the specification of the batteries.
. The charging method as claimed in, further comprising the steps of: progressively increasing the output voltage of the charging circuit to the maximum target voltage.
. The charging method as claimed in, further comprising the steps of: when the end condition is met, controlling the battery balancing circuit to continue to perform the voltage balancing operation on the battery string.
. The charging method as claimed in, wherein the batteries are lead-acid batteries, the maximum chargeable voltage is a cycle use charging voltage defined by the specification of the batteries, and the standard charging voltage is a standby use charging voltage defined by the specification of the batteries.
. The charging method as claimed in, wherein the batteries are lithium batteries.
. The charging method as claimed in, further comprising the steps of: reducing the output energy of the charging circuit by reducing the output current of the charging circuit.
. The charging method as claimed in, further comprising the steps of: when the end condition is met, increasing the output current of the charging circuit, so that the charging circuit can continue charging the battery string accordingly and thereby making the voltage of the battery string rises to a maximum target voltage, wherein the maximum target voltage is greater than an initial target voltage of the charging circuit, the value of the maximum target voltage is a product of the number of the batteries and a maximum chargeable voltage defined by the specification of the batteries, and the value of the initial target voltage is a product of the number of the batteries and a standard charging voltage defined by the specification of the batteries.
. The charging method as claimed in, further comprising the steps of: progressively increasing the output current of the charging circuit, thereby progressively increasing the voltage of the battery string to the maximum target voltage.
. The charging method as claimed in, further comprising the steps of: when the end condition is met, controlling the battery balancing circuit to continue to perform the voltage balancing operation on the battery string.
. The charging method as claimed in, wherein the batteries are lead-acid batteries, the maximum chargeable voltage is a cycle use charging voltage defined by the specification of the batteries, and the standard charging voltage is a standby use charging voltage defined by the specification of the batteries.
. The charging method as claimed in, wherein the batteries are lithium batteries.
. The charging method as claimed in, wherein the start condition is that the voltage difference between the voltage of any battery and the average voltage of the batteries is greater than or equal to a second threshold value, and the end condition is that the voltage difference between the voltage of any battery and the average voltage of the batteries is less than a third threshold value, wherein the third threshold value is less than the second threshold value.
. The charging method as claimed in, wherein the start condition is that the voltage difference between any two batteries is greater than or equal to a second threshold value, and the end condition is that the voltage difference between any two batteries is less than a third threshold value, wherein the third threshold value is less than the second threshold value.
. A charging device, used for charging a battery string consisting of batteries connected in series, the charging device comprising:
. The charging device as claimed in, wherein the control circuit comprises reducing the output energy of the charging circuit by reducing the output voltage of the charging circuit.
. The charging device as claimed in, wherein when it is determined that the end condition is met, the control circuit increases the output voltage of the charging circuit to a maximum target voltage, so that the charging circuit can continue charging the battery string accordingly, wherein the maximum target voltage is greater than an initial target voltage of the charging circuit, the value of the maximum target voltage is a product of the number of the batteries and a maximum chargeable voltage defined by the specification of the batteries, and the value of the initial target voltage is a product of the number of the batteries and a standard charging voltage defined by the specification of the batteries.
. The charging device as claimed in, wherein the control circuit comprises progressively increasing the output voltage of the charging circuit to the maximum target voltage.
. The charging device as claimed in, wherein when it is determined that the end condition is met, the control circuit further controls the battery balancing circuit to continue to perform the voltage balancing operation on the battery string.
. The charging device as claimed in, wherein the batteries are lead-acid batteries, the maximum chargeable voltage is a cycle use charging voltage defined by the specification of the batteries, and the standard charging voltage is a standby use charging voltage defined by the specification of the batteries.
. The charging device as claimed in, wherein the batteries are lithium batteries.
. The charging device as claimed in, wherein the control circuit comprises reducing the output energy of the charging circuit by reducing the output current of the charging circuit.
. The charging device as claimed in, wherein when the end condition is met, the control circuit increases the output current of the charging circuit, so that the charging circuit can continue charging the battery string accordingly and thereby making the voltage of the battery string rises to a maximum target voltage, wherein the maximum target voltage is greater than an initial target voltage of the charging circuit, the value of the maximum target voltage is a product of the number of the batteries and a maximum chargeable voltage defined by the specification of the batteries, and the value of the initial target voltage is a product of the number of the batteries and a standard charging voltage defined by the specification of the batteries.
. The charging device as claimed in, wherein the control circuit comprises progressively increasing the output current of the charging circuit, thereby progressively increasing the voltage of the battery string to the maximum target voltage.
. The charging device as claimed in, wherein when it is determined that the end condition is met, the control circuit further controls the battery balancing circuit to continue to perform the voltage balancing operation on the battery string.
. The charging device as claimed in, wherein the batteries are lead-acid batteries, the maximum chargeable voltage is a cycle use charging voltage defined by the specification of the batteries, and the standard charging voltage is a standby use charging voltage defined by the specification of the batteries.
. The charging device as claimed in, wherein the batteries are lithium batteries.
. The charging device as claimed in, wherein the start condition is that the voltage difference between the voltage of any battery and the average voltage of the batteries is greater than or equal to a second threshold value, and the end condition is that the voltage difference between the voltage of any battery and the average voltage of the batteries is less than a third threshold value, wherein the third threshold value is less than the second threshold value.
. The charging device as claimed in, wherein the start condition is that the voltage difference between any two batteries is greater than or equal to a second threshold value, and the end condition is that the voltage difference between any two batteries is less than a third threshold value, wherein the third threshold value is less than the second threshold value.
. An on-line uninterruptible power system, which adopts the charging device as claimed in.
. An off-line uninterruptible power system, which adopts the charging device as claimed in.
. A line-interactive uninterruptible power system, which adopts the charging device as claimed in.
Complete technical specification and implementation details from the patent document.
The present invention relates to the technical field of battery charging, and in particular, to a charging method, a corresponding charging device and various corresponding uninterruptible power systems.
Generally speaking, when charging a battery string, it is very likely that the battery voltage will be unbalanced. Although there are many reasons for battery voltage unbalance, regardless of the cause, once battery voltage unbalance occurs, it is easy to cause some batteries to be overcharged. Once a battery is overcharged, the life of the overcharged battery is extremely easy to be reduced or even damaged (such as visible swelling in appearance).
An object of the present invention is to provide a charging method, which can prevent batteries from overcharging.
Another object of the present invention is to provide a charging device using the aforementioned charging method.
Still another object of the present invention is to provide an on-line uninterruptible power system adopting the aforementioned charging device.
Still another object of the present invention is to provide an off-line uninterruptible power system adopting the aforementioned charging device.
Still another object of the present invention is to provide a line-interactive uninterruptible power system adopting the aforementioned charging device.
To achieve the above object, the present invention provides a charging method, which is suitable for a battery string consisting of batteries connected in series. The charging method comprises the following steps: controlling a charging circuit to charge the battery string and measuring a voltage of each battery; determining whether a start condition for performing a voltage balancing operation is met based on the voltage values of the batteries, and determine whether the voltage value of any battery is greater than or equal to a first threshold value; whenever the start condition is met, controlling a battery balancing circuit to start performing the voltage balancing operation on the battery string until the voltage values of the batteries meet an end condition of the voltage balancing operation; and whenever it is determined that the voltage value of any battery is greater than or equal to the first threshold value, reducing the output energy of the charging circuit until the voltage value of any battery is less than the first threshold value.
To achieve the above another object, the present invention provides a charging device for charging a battery string consisting of batteries connected in series. The charging device comprises a charging circuit, a battery balancing circuit and a control circuit. The charging circuit is electrically coupled to two terminals of the battery string. The battery balancing circuit is electrically coupled to the two terminals of each battery for measuring a voltage of each battery and performing a voltage balancing operation on the battery string. The control circuit is also used to determine whether a start condition for performing the voltage balancing operation is met based on the voltage values of the batteries, and to determine whether the voltage value of any battery is greater than or equal to a first threshold value. Whenever the start condition is met, the control circuit controls the battery balancing circuit to start performing the voltage balancing operation on the battery string until the voltage values of the batteries meet an end condition of the voltage balancing operation, and whenever it is determined that the voltage value of any battery is greater than or equal to the first threshold value, the control circuit reduces the output energy of the charging circuit until the voltage value of any battery is less than the first threshold value.
In order to make the above objects, technical features and gains after actual implementation more obvious and easy to understand, in the following, the preferred embodiments will be described with reference to the corresponding drawings and will be described in more detail.
The characteristics, contents, advantages and achieved effects of the present disclosure will become more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present disclosure.
As required, detailed embodiments are disclosed herein. It must be understood that the disclosed embodiments are merely exemplary of and may be embodied in various and alternative forms, and combinations thereof. As used herein, the word “exemplary” is used expansively to refer to embodiments that serve as illustrations, specimens, models, or patterns. The figures are not necessarily to scale and some features may be exaggerated or minimized to show details of particular components. In other instances, well-known components, systems, materials, or methods that are known to those having ordinary skill in the art have not been described in detail in order to avoid obscuring the present disclosure. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art.
shows an uninterruptible power system according to an embodiment of the present invention. Please refer to. From the circuit structure shown in, it can be seen that the uninterruptible power systemis an off-line uninterruptible power system (Off-line UPS). The uninterruptible power systemcomprises a filter unit, a switch unit, a DC-AC conversion circuit, a switch unit, a filter unit, a charging circuit, a battery pack, a battery balancing circuit, a control circuitand a bypass path.
The switch unitis electrically coupled to one terminal of the bypass path, and is electrically coupled to the AC power source (e.g., AC mains) through the filter unit. The switch unitis electrically coupled to the other terminal of the bypass path, and is electrically coupled to an output endof the uninterruptible power systemthrough the filter unit. The charging circuitis electrically coupled to the battery pack, and is electrically coupled to the AC power source through the filter unit. The DC-AC conversion circuitis electrically coupled between the battery packand the switch unit. The battery balancing circuitis electrically coupled to the battery pack.
In addition, the switch unit, the DC-AC conversion circuit, the switch unit, the charging circuitand the battery balancing circuitare electrically coupled to the control circuitto be controlled by the control circuit. For example, the control circuitcan control the operation of the switch unit, so as to determine whether to electrically couple the output terminal of the DC-AC conversion circuitto the filter unit, or to electrically couple the bypass pathto the filter unit. In addition, the charging circuit, the battery balancing circuitand the control circuitmake up the charging device of the present invention.
shows the electrical coupling relationship between the charging device and the battery pack. Please refer to. In this embodiment, the battery packconsists of a battery string, and the battery string consists of batteries (as indicated by labels_to_N, where N is a natural number) connected in series. In addition, the charging circuit, the battery balancing circuitand the control circuitmake up the aforementioned charging device. The charging circuitis electrically coupled to two terminals of the battery string. The battery balancing circuitis electrically coupled to the two terminals of each battery, for measuring a voltage of each battery, and for performing a voltage balancing operation on the battery string. The control circuitis electrically coupled to the charging circuitand the battery balancing circuitto control their operations. In this embodiment, the control circuituses a control signal CS to control the operation of the charging circuit.
In this embodiment, the battery balancing circuitcomprises switches_-_N, resistors_-_N and a microprocessor. As shown in, one terminal of each resistor is electrically coupled to the positive terminal of one of the batteries, and the other terminal of each resistor is electrically coupled to the negative terminal of one of the batteries through one of the switches. In addition, the microprocessoris electrically coupled to the positive terminal of each battery for voltage measurement. The microprocessoris also electrically coupled to the control terminal of each switch to control the operations of the switches. The microprocessorcan also transmit the measured voltage values to the control circuit, so that the control circuitcan determine the charging status of each battery accordingly.
is a flow chart of a charging method according to an embodiment of the present invention. Please refer to. In this method, the control circuitfirst controls the charging circuitto charge the battery string (consisting of batteries_-_N connected in series), and controls the battery balancing circuitto measure a voltage of each battery (as shown in step S). To facilitate understanding, the following uses a battery string with 6 batteries as an example.is used to illustrate one of the charging processes of the aforementioned battery string. Please also refer to. Assuming that the charging circuitoperates in a constant voltage charging mode, in this embodiment, the control circuitcontrols the charging circuitto first output an initial target voltage to start charging the battery string. The value of the initial target voltage is a product of the number of the batteries_-_N and a standard charging voltage defined by the specification of the batteries_-_N. The aforementioned batteries may all be lead-acid batteries or all lithium batteries. Assuming that the aforementioned batteries are lead-acid batteries, the aforementioned standard charging voltage is a standby use charging voltage defined by the specification of the lead-acid batteries. The standby use charging voltage is also called float use charging voltage. In this embodiment, the initial target voltage is 13.8V.
Next, the control circuitdetermines whether a start condition for performing the voltage balancing operation is met based on the voltage values of the batteries, and determines whether the voltage value of any battery is greater than or equal to a battery protection threshold value (as shown in step S). There are two kinds of start condition, and which start condition is adopted can be decided according to actual design requirements. The first kind of the start condition is that the voltage difference between the voltage of any battery and the average voltage of the batteries is greater than or equal to a threshold valueVs, while the second kind of the start condition is that the voltage difference between any two batteries is greater than or equal to the threshold valueVs. The threshold valueVs can be determined according to actual design requirements. In this embodiment, the threshold value ΔVs is 0.1V. In addition, the battery protection threshold value is also determined based on actual design requirements. In this embodiment, the battery protection threshold value is 14.6V.
Afterwards, whenever it is determined that the start condition is met, the control circuitcontrols the battery balancing circuitto start performing the voltage balancing operation on the battery string until the voltage values of the batteries meet an end condition of the voltage balancing operation (as shown in step S), and whenever it is determined that the voltage value of any battery is greater than or equal to the battery protection threshold value, the control circuitreduces the output energy of the charging circuituntil the voltage value of any battery is less than the battery protection threshold value (as shown in step S). Since steps Sand Shave respective execution conditions, there is no order of execution of steps Sand S.
As can be seen from, after the battery string is charged for a period of time, the voltages of the batteries become unbalanced. Therefore, the control circuitcontrols the battery balancing circuitto start performing the voltage balancing operation on the battery string. It can also be seen fromthat during the voltage balancing operation, the voltage value of batteryexceeds the battery protection threshold value (i.e., 14.6V). At this time, the control circuitreduces the output energy of the charging circuituntil the voltage value of any battery is less than the battery protection threshold value. Since the charging circuitin this embodiment operates in constant voltage charging mode, in this embodiment, the control circuitreduces the output energy of the charging circuitby reducing the output voltage of the charging circuit. For example, the output voltage of the charging circuitis reduced by a predetermined value, a predetermined ratio, or even reduced to 0V.
It can also be seen fromthat since the output energy of the charging circuitis reduced, the voltage values of some batteries begin to drop sharply, making the voltage value of each battery less than the battery protection threshold value (i.e., 14.6V). In addition, as the voltage balancing operation proceeds, the voltage values of the batteries become more and more consistent. Certainly, the control circuitcan also dynamically adjust the output voltage of the charging circuit. For example, control circuitreduces the output voltage of the charging circuitas long as the voltage value of any battery is greater than or equal to the battery protection threshold value, and increases the output voltage of the charging circuitas long as the voltage values of all batteries are less than the battery protection threshold value.
As the voltage balancing operation proceeds, the control circuitalso periodically or irregularly determines whether the voltage values of the batteries meet the end condition of the voltage balancing operation. There are two kinds of end condition, and which end condition is adopted can be decided according to actual design requirements. The first kind of the end condition is that the voltage difference between the voltage of any battery and the average voltage of the batteries is less than a threshold value Vb, while the second kind of the end condition is that the voltage difference between any two batteries is less than the threshold value Vb. The threshold value Vb can be determined according to actual design requirements, but the threshold value Vb should be less than the threshold valueVs. In this embodiment, the threshold value Vb is 0.05V.
As can be seen from, after the voltage balancing operation is performed for a period of time, the voltage values of the batteries in the battery string gradually become consistent. When the voltage values of the batteries meet the end condition of the voltage balancing operation, the control circuitincreases the output voltage of the charging circuitto the maximum target voltage, so that the charging circuitcan continue charging the battery string accordingly. The maximum target voltage is greater than the aforementioned initial target voltage. The value of the maximum target voltage is a product of the number of the batteries_-_N and a maximum chargeable voltage defined by the specification of the batteries_-_N. Assuming that the aforementioned batteries are lead-acid batteries, the aforementioned maximum chargeable voltage is a cycle use charging voltage defined by the specification of the lead-acid batteries. In this embodiment, the maximum target voltage is 14.4V.
As shown in, in this embodiment, the control circuitprogressively increases the output voltage of the charging circuitto the maximum target voltage of 14.4V. In addition, when the end condition of the voltage balancing operation is met, the control circuitcan still control the battery balancing circuitto continue to perform the voltage balancing operation on the battery string, so that the voltages of the batteries can still maintain balanced during the period when the output voltage of the charging circuitgradually increases to the maximum target voltage.
Certainly, when the end condition of the voltage balancing operation is met, the control circuitcan also control the battery balancing circuitto stop performing the voltage balancing operation. However, the drawback of doing so is that the voltages of the batteries may not maintain balanced during the period when the output voltage of the charging circuitgradually increases to the maximum target voltage. In addition, the control circuitmay not use the aforementioned incremental manner to increase the output voltage of the charging circuitto the maximum target voltage, but rather control the charging circuitto directly pull up the output voltage to the maximum target voltage. Furthermore, during the process of charging the battery string, the control circuitmay also control the charging circuitto use the maximum target voltage throughout the entire process to charge the battery string.
Although in the foregoing embodiments, the charging circuitoperates in the constant voltage charging mode, this is not intended to limit the present invention. For example, the charging circuitmay also operate in a constant current charging mode. If the charging circuitoperates in the constant current charging mode, the control circuitcan change the output energy of the charging circuitby adjusting the output current of the charging circuit, so that the voltage of the battery string can reach the aforementioned initial target voltage and the aforementioned maximum target voltage. For example, when the end condition of the voltage balancing operation is met, the control circuitcan increase the output current of the charging circuit, so that the charging circuitcan continue charging the battery string accordingly and thereby making the voltage of the battery string rises to the maximum target voltage.
The control circuitmay increase the output current of the charging circuitin an incremental manner, thereby increasing the voltage of the battery string to the maximum target voltage. Certainly, the control circuitmay not use the incremental manner to increase the output current of the charging circuit, but rather control the charging circuitto directly pull up the output current to a predetermined value, thereby making the voltage of the battery string to be directly pulled up to the maximum target voltage. In addition, during the process of charging the battery string, the control circuitmay also control the charging circuitto use the predetermined value of the output current throughout the entire process to charge the battery string. Furthermore, as mentioned above, once the control circuitneeds to reduce the output energy of the charging circuit, it can do so by reducing the output current of the charging circuit.
In addition, although in the above embodiments, the battery packconsists of a battery string, this is not intended to limit the invention. Those skilled in the art should know that the battery packcan consist of at least two battery strings connected in parallel.
Based on the above teachings, it can be seen that through the voltage balancing operation and the setting of the battery protection threshold value, the present invention can effectively prevent every single battery from being overcharged. In addition, since no battery will be overcharged, the present invention can further shorten the time required for the voltage balancing operation. Furthermore, by setting the maximum target voltage, the present invention can also increase the endurance of every single battery.
In addition, based on the above teachings, skilled in the art should know that the concept of the present invention can also be applied to other uninterruptible power systems with different architectures, please refer to the following description.
shows an uninterruptible power system according to another embodiment of the present invention. Please refer to. From the circuit structure shown in, it can be seen that the uninterruptible power systemis an off-line uninterruptible power system. Compared with the off-line uninterruptible power system shown in, the off-line uninterruptible power system shown infurther comprises a DC-DC conversion circuit. The DC-DC conversion circuitis electrically coupled between the battery packand the input terminal of the DC-AC conversion circuit, and is electrically coupled to the control circuitto be controlled by the control circuit.
shows an uninterruptible power system according to still another embodiment of the present invention. Please refer to. From the circuit structure shown in, it can be seen that the uninterruptible power systemis a line-interactive uninterruptible power system. Compared with the off-line uninterruptible power system shown in, the line-interactive uninterruptible power system shown infurther comprises an automatic voltage regulation circuit (AVR circuit). The automatic voltage regulation circuitis disposed on the bypass path, and is electrically coupled to the control circuitto be controlled by the control circuit.
shows an uninterruptible power system according to still another embodiment of the present invention. Please refer to. From the circuit structure shown in, it can be seen that the uninterruptible power systemis a line-interactive uninterruptible power system. Compared with the line-interactive uninterruptible power system shown in, the line-interactive uninterruptible power system shown infurther comprises a DC-DC conversion circuit. The DC-DC conversion circuitis electrically coupled between the battery packand the input end of the DC-AC conversion circuit, and is electrically coupled to the control circuitto be controlled by the control circuit.
shows an uninterruptible power system according to still another embodiment of the present invention. Please refer to. From the circuit structure shown in, it can be seen that the uninterruptible power systemis an on-line uninterruptible power system. Compared with the off-line uninterruptible power system shown in, the on-line uninterruptible power system shown infurther comprises a power factor correction circuit (PFC circuit). The power factor correction circuitis electrically coupled between the switch unitand the input terminal of the DC-AC conversion circuit, and is electrically coupled to the control circuitto be controlled by the control circuit. In addition, in this embodiment, the control circuitcan control the operation of the switch unit, so as to determine whether to electrically couple the filter unitto the bypass path, or to electrically couple the filter unitto the input terminal of the power factor correction circuit.
While the disclosure has been described by way of example and in terms of the preferred embodiments, it is to be understood that the disclosure is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.
Unknown
December 25, 2025
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